Editorial Note on Part 393
Editorial Note: Nomenclature changes to part 393 appear at 66 FR 49874, Oct. 1, 2001.

§ 393.17 Lamps and reflectors—combinations in driveaway-towaway operation. A combination of motor vehicles engaged in driveaway-towaway operation must be equipped with operative lamps and reflectors conforming to the rules in this section. ( a ) The towing vehicle must be equipped as follows: ( 1 ) On the front, there must be at least two headlamps, an equal number at each side, two turn signals, one at each side, and two clearance lamps, one at each side.
( 2 ) On each side, there must be at least one side-marker lamp, located near the front of the vehicle.
( 3 ) On the rear, there must be at least two tail lamps, one at each side, and two stop lamps, one at each side.
( b ) Except as provided in paragraph (c) of this section, the rearmost towed vehicle of the combination (including the towed vehicles of a tow-bar combination, the towed vehicle of a single saddle-mount combination, and the rearmost towed vehicle of a double or triple saddle-mount combination) or, in the case of a vehicle full-mounted on a saddle-mount vehicle, either the full-mounted vehicle or the rearmost saddle-mounted vehicle must be equipped as follows: ( 1 ) On each side, there must be at least one side-marker lamp, located near the rear of the vehicle.
( 2 ) On the rear, there must be at least two tail lamps, two stop lamps, two turn signals, two clearance lamps, and two reflectors, one of each type at each side. In addition, if any vehicle in the combination is 80 inches or more in overall width, there must be three identification lamps on the rear.
( c ) If the towed vehicle in a combination is a mobile structure trailer, it must be equipped in accordance with the following lighting devices. For the purposes of this part, *mobile structure trailer* means a trailer that has a roof and walls, is at least 10 feet wide, and can be used off road for dwelling or commercial purposes. ( 1 ) When the vehicle is operated in accordance with the terms of a special permit prohibiting operation during the times when lighted lamps are required, it must have on the rear— ( i ) Two stop lamps, one on each side of the vertical centerline, at the same height, and as far apart as practicable;
( ii ) Two tail lamps, one on each side of the vertical centerline, at the same height, and as far apart as practicable;
( iii ) Two red reflex reflectors, one on each side of the vertical centerline, at the same height, and as far apart as practicable; and
( iv ) Two turn signal lamps, one on each side of the vertical centerline, at the same height, and as far apart as practicable.
( 2 ) At all other times, the vehicle must be equipped as specified in paragraph (b) of this section.
( d ) An intermediate towed vehicle in a combination consisting of more than two vehicles (including the first saddle-mounted vehicle of a double saddle-mount combination and the first and second saddle-mount vehicles of a triple saddle-mount combination) must have one side-marker lamp on each side, located near the rear of the vehicle.
(49 U.S.C. 304, 1655; 49 CFR 1.48(b) and 301.60)
[40 FR 36126, Aug. 19, 1975, as amended at 47 FR 47837, Oct. 28, 1982; 70 FR 48044, Aug. 15, 2005; 77 FR 59828, Oct. 1, 2012; 80 FR 59075, Oct. 1, 2015]